As satellites and space-based instruments play an ever increasing role in our daily lives, scientists and engineers are continually researching new ways of placing such objects in orbit in a cost-effective and safe manner. Currently, most satellites are placed in orbit using a dedicated launch vehicle. In addition to the large aerodynamic loads and high temperatures produced by the launch vehicle during liftoff, a payload such as a satellite is subjected to high levels of acoustic energy from the launch vehicle's engines. Typical launch vehicle engines produce sound pressure levels nearing 155 dB at the payload position. To withstand this large amount of acoustic energy, a payload needs to be carefully protected or it may literally rattle apart.
To reduce the level of acoustic energy to which the payload is subjected, a launch vehicle includes a payload shroud. The payload shroud surrounds the payload and absorbs acoustic energy as well as protects the payload from dynamic air pressure and heating during liftoff, as well as such mundane hazards as wind, rain, snow, hail and lightning, etc., while the payload is sitting on the launch pad. In the past, payload shrouds were built of aluminum or composite materials such as carbon/epoxy honeycomb. Fiber glass blankets were placed around the inside of the shroud to further absorb acoustic energy produced by the launch vehicle's engines and to provide thermal insulation. Prior art payload shrouds suffer from at least three related problems: one, they are excessively heavy; two, they are excessively costly; and three, they do not provide sufficient acoustic protection for the payload. While some existing payload shrouds have been designed to be relatively lightweight, their poor acoustic performance requires the addition of heavy fiber glass blankets to meet noise requirements. These fiber glass blankets introduce another problem in addition to the increased weight and cost--they are a major source of contamination due to fiber glass dust which collects in large quantities within the blankets. Because it is virtually impossible to repair a payload in space, payloads such as satellites are typically constructed in clean rooms to prevent dust and din from fouling any mechanism before the payload is placed in orbit. To subject the payload to a dusty environment during launch defeats the purpose of the clean room construction and only increases the chance that it may malfunction in space.
Therefore, a need exists for a low-cost, lightweight payload shroud structure that provides good acoustic protection and is not a source of contaminates. The payload shroud structure should be able to be manufactured using low-cost fabrication methods and should have a low life cycle cost.